Influence of Laser Hardening to the Sliding Wear Resistance of the PVD (Al, Ti) N-G and nACo® Coatings

In the present article, the effect of laser hardening of the carbon steel C45, previously coated by the physical vapour deposition (PVD) process is studied. The (Al, Ti) N-G and nACo (R) (nc-AlxTi1-xN/alpha-Si3N4) coatings were applied. The hardening was achieved by the use of the Nd:YAG laser with the laser beam power density of 1945 W/cm(2) and scan speed of 300 mm/min. Laser hardening lead to the formation of hardened layer under both coatings, consisting of austenite and ferrite. The approximate depth of the hardened layer and maximal microhardness was approximately 0.2 mm and 955 HV0.05 and 0.1 mm and 520 HV0.05 in the case of the (Al, Ti) N-G and the nACo (R) coating, respectively. After laser hardening the sliding wear of the (Al, Ti) N-G coating increased 25 % and that of the nACo (R) coating - 5 %.